1. Field of the Invention
This invention is directed to clamp apparatuses for clamping together a drive shaft of a wellbore top drive system and another item, e.g. mud saver, a saver sub or an internal blowout preventer or to clamp together a mud saver and a saver sub; and methods of their use.
2. Description of Related Art
The prior art discloses a variety of clamping apparatuses for clamping together a top, drive shaft or part of a tubular string below a top drive threadedly connected to another item, e.g. a top drive shaft connected to a mud saver or a mud saver and another item, e.g. a saver sub. For example, and not by way of limitation, a prior art clamping apparatus is disclosed in co-owned U.S. Pat. No. 7,188,686 which shows clamping apparatuses for clamping together, e.g. a top drive system threadedly connected with another item. U.S. Pat. Nos. 4,458,768; 5,433,279; 6,276,450; 4,813,493; 6,705,405; 4,800,968; 4,878,546; 4,872,577; 4,753,300; 6,536,520; 6,679,333 disclose various top drive systems. The cited patents are incorporated fully herein for all purposes.